I believe SETI is the new name for what was formerly Test Engineer. I think they changed the name because it was a better description of what they do. I suspect it also made it easier to hire for, although that might just be due to the aforementioned reason.
This is based off what I was told when I interviewed there a year ago.
From what I understand, SEs in Test are now called SETI, but I could be wrong. It sounds like SETI does all the things the test engineers do in Google (I interviewed with SETI a half-year ago).